An enzyme electrode used for a biosensor has a structure in which electrons generated by an enzyme reaction are received by the electrode, and the enzyme electrode may comprise an electrode and a detection layer in which enzymes and conductive particles are immobilized on the surface of the electrode using a crosslinking agent or a binder. Patent Literature 1 describes an enzyme electrode comprising an electrode and a detection layer, wherein the detection layer has an enzyme, conductive particles, and a polymer that forms an amide or ester bond with at least one of the enzyme and the conductive particle.
On the other hand, Non-patent Literature 1 has disclosed a method of using a molecule that forms a self assembled monolayer (SAM) to efficiently transfer electrons between an enzyme and a current collector (electrode). In a specific illustration in the Non-patent Literature 1, an enzyme, such as HRP (Horseraddish Peroxydase), was immobilized on the surface of the current collector via a SAM-forming molecule. However, regarding the method to immobilize enzymes via SAM-forming molecules by adsorption or the like, there has been no report of successful immobilization of glucose dehydrogenase which is one of the most used enzymes for glucose measurement biosensors. The reason may be that the catalytic site of glucose dehydrogenase is located at the center of the enzyme and thus electron transfer to the current collector is hardly occurred even when the enzyme is fixed in the vicinity of the electrode; and in particular, in the immobilization of the enzyme by random adsorption or the like, the distance between the current collector and the enzyme can not be controlled.